Construct the Appropriate Two-Sigma Control Chart for the Sample Observations

Essay

Construct the appropriate two-sigma control chart for the sample observations listed below. $$\begin{array} { l l l l l l l l l l r r } \text { Observation } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 & 11 \\\hline \text { Num. defects per unit } & 9 & 4 & 3 & 5 & 6 & 3 & 4 & 2 & 3 & 2 & 3\end{array}$$